JPWO2022185903A5 - - Google Patents

Description

The present invention relates to a carbon dioxide adsorption battery and a charging/discharging device.

Carbon dioxide is not only a widely occurring substance on earth, accounting for about 0.04% of the atmosphere, but also widely used in industry. Examples of ways to use carbon dioxide include carbonated drinks, bath additives, foaming gas such as fire extinguishers, dry ice used for cooling, and air for emergency replenishment of bicycle tires. Moreover, carbon dioxide can also be used as an extraction solvent for extracting caffeine and the like by bringing it into a supercritical state. Carbon dioxide is also used in lasers used for processing in the industrial field and carbon dioxide lasers used in medical laser scalpels and the like. Furthermore, carbon dioxide may be used as a refrigerant for the compressor instead of a fluorocarbon refrigerant. Carbon dioxide is also used in the agricultural field, for example, for forced cultivation of strawberries and carbon dioxide fertilization for accelerating the growth of plants such as aquatic plants in ornamental aquariums. Carbon dioxide is also used for CA (Controlled Atomosphere) storage of fresh agricultural products.

As mentioned above, carbon dioxide is used in various fields, and therefore there is a need for a method of obtaining carbon dioxide, such as by separating carbon dioxide from a gas containing carbon dioxide such as air. Carbon dioxide is also said to be a cause of global warming. For this reason as well, there is a need to separate carbon dioxide from a gas containing carbon dioxide and utilize the carbon dioxide. In order to utilize carbon dioxide, there is a need to develop, for example, a method for separating carbon dioxide from a gas containing carbon dioxide, an apparatus for adsorbing and separating carbon dioxide, and an apparatus for utilizing carbon dioxide.

Various methods have been proposed for separating carbon dioxide from a mixed gas containing oxygen and carbon dioxide, such as air. This separation method involves, for example, using a carbon dioxide adsorbent to adsorb carbon dioxide in the air, and then desorbing the carbon dioxide adsorbed by the adsorbent to separate carbon dioxide from the air. Examples include a method to do so. Examples of adsorbents that adsorb carbon dioxide include activated carbon, amine solvents, and aqueous potassium carbonate solutions. In addition, as a method for separating carbon dioxide using an adsorbent, more specifically, carbon dioxide is adsorbed onto the adsorbent under high pressure by applying pressure, and then the pressure is reduced to remove carbon dioxide from the adsorbent. Examples include a pressure swing adsorption (PSA) method in which desorption is performed. Examples of the adsorbent used when separating carbon dioxide by this PSA method include the adsorbent described in Patent Document 1.

Patent Document 1 describes a carbon dioxide adsorbent comprising a composition in which 2 to 80 equivalent % of the sodium ions of a sodium-containing aluminosilicate are ion-exchanged with barium ions. Patent Document 1 discloses that it is possible to provide an adsorbent that has a high carbon dioxide selection ratio and a large absorption capacity even under conditions of high moisture content. Further, Patent Document 1 discloses that this adsorbent can be suitably used to separate and concentrate carbon dioxide by the PSA method.

Examples of devices that adsorb and separate carbon dioxide include the acidic gas adsorption/desorption device described in Patent Document 2 and the carbon dioxide separation device described in Patent Document 3.

Patent Document 2 describes an acidic gas adsorption/desorption layer including a base material and a compound capable of adsorbing and desorbing acidic gas such as carbon dioxide by performing oxidation and reduction, and the acidic gas adsorption/desorption layer. An acidic gas adsorption/desorption device is described having a pair of electrodes sandwiching a layer.

Patent Document 3 discloses that an electrolyte layer and a pair of electrodes provided on the electrolyte layer with the electrolyte layer in between are provided with a voltage applying unit that applies a voltage between the pair of electrodes, A carbon dioxide separation device in which the pair of electrodes are gas permeable electrodes, and the electrolyte layer includes an electrolytic solution capable of dissolving carbon dioxide and a redox compound having an N-oxy radical group in the molecule. is listed.

Furthermore, examples of devices that utilize carbon dioxide include the batteries described in Non-Patent Document 1 and Non-Patent Document 2.

Non-Patent Document 1 proposes a battery that is charged while absorbing carbon dioxide as a method of utilizing carbon dioxide.

Non-Patent Document 2 proposes a carbon dioxide rechargeable battery incorporating a redox system. Specifically, a carbon dioxide rechargeable battery has been proposed in which poly-1,4-anthraquinone and polyvinylferrocene are used in the negative and positive electrodes, respectively.

Japanese Patent Application Publication No. 7-39752 JP2015-36128A JP 2018-1131 Publication

Aliza Khurram et al. , “Tailoring the Discharge Reaction in Li-CO2 Batteries through Corporation of CO2 Capture Chemistry”, Joule 2, 2649-2666, December 19, 2018 Sahag Voskian et al. , “Faradaiic electro-swing reactive adsorption for CO2 Capture”, Energy & Environmental Science, 2019, 12, 3530-3547

An object of the present invention is to provide a carbon dioxide adsorption battery that can be charged while easily adsorbing carbon dioxide from a gas containing carbon dioxide. Another object of the present invention is to provide a charging/discharging device including the carbon dioxide adsorption battery.

One aspect of the present invention is a negative electrode , a positive electrode, a separator disposed between the negative electrode and the positive electrode , and a separator disposed between the negative electrode and the separator and between the positive electrode and the separator, respectively. the negative electrode is a gas-permeable electrode, and the electrolyte layer includes an electrolytic solution capable of dissolving carbon dioxide and a redox compound having an N-oxy radical group in the molecule. , the separator is a carbon dioxide adsorption battery in which the separator suppresses permeation of the redox compound and allows the electrolyte to permeate.

FIG. 1 is a schematic cross-sectional view showing an example of the configuration of a carbon dioxide adsorption battery according to an embodiment of the present invention during charging. FIG. 2 is a schematic cross-sectional view showing an example of the configuration during discharging in the carbon dioxide adsorption battery according to the embodiment of the present invention. FIG. 3 is a schematic cross-sectional view showing another example of the configuration at the time of charging in the carbon dioxide adsorption battery according to the embodiment of the present invention. FIG. 4 is a schematic cross-sectional view showing another example of the configuration at the time of charging in the carbon dioxide adsorption battery according to the embodiment of the present invention. FIG. 5 is a schematic cross-sectional view showing another example of the configuration during discharging in the carbon dioxide adsorption battery according to the embodiment of the present invention. FIG. 6 is a schematic diagram showing the configuration of an example of a charging/discharging device according to an embodiment of the present invention.

The method of separating carbon dioxide by the PSA method, for example, the method using an adsorbent described in Patent Document 1, requires pressurization and depressurization as described above. In addition, if the carbon dioxide separation method uses an adsorbent, even if it is a method other than the PSA method, it is possible to not only adsorb carbon dioxide on the adsorbent but also desorb the carbon dioxide adsorbed on the adsorbent. This operation requires, for example, heat treatment. For this reason, carbon dioxide separation methods using adsorbents sometimes require a relatively large amount of energy or relatively large equipment.

As a method for separating carbon dioxide, there is a need for a simple method that can separate carbon dioxide without using a lot of energy or using relatively large equipment.

According to Patent Document 2, it is disclosed that adsorption and desorption of acidic gas can be performed in a solid state. Specifically, in the method described in Patent Document 2, first, a voltage is applied between the electrodes to cause the acidic gas adsorption/desorption layer to adsorb acidic gas. Thereafter, the voltage applied between the electrodes is reversed so that the current flowing through the acidic gas adsorption/desorption layer arranged between the electrodes is in the opposite direction to that during adsorption, and the acidic gas is removed from the acidic gas adsorption/desorption layer. to detach. As described above, in the method described in Patent Document 2, when adsorbing acidic gas to the acidic gas adsorption/desorption layer and when desorbing the adsorbed acidic gas from the acidic gas adsorption/desorption layer, the difference between the electrodes is Reverse the voltage applied to the Even if an attempt was made to separate carbon dioxide using the apparatus described in Patent Document 2, focusing on carbon dioxide as an acidic gas, as described above, it was necessary to reverse the voltage applied between the electrodes. For this reason, the method described in Patent Document 2 may require a relatively large amount of energy or a relatively large device, as in the case of using the adsorbent described in Patent Document 1. there were.

Patent Document 3 discloses that it is possible to provide a carbon dioxide separation device that can easily separate carbon dioxide from a gas containing carbon dioxide. Patent Document 3 states that this carbon dioxide separation device can separate carbon dioxide without reversing the voltage applied between a pair of electrodes between adsorbing and releasing carbon dioxide. Disclosed. Specifically, by applying a voltage between a pair of electrodes provided in the carbon dioxide separator, carbon dioxide that has passed through one electrode is bonded to a compound having an N-oxy radical group in the molecule, It is disclosed that this compound to which carbon dioxide is bound flows to the other electrode side, where carbon dioxide is released from the compound.

According to the study by the present inventor, the carbon dioxide separator described in Patent Document 3 was unable to store electricity. Specifically, in the carbon dioxide separator described in Patent Document 3, as described above, by applying a voltage between the pair of electrodes, the flow of carbon dioxide is continuously performed. During separation, current always flows in one direction, so it is thought that electricity cannot be stored.

Non-Patent Document 1 discloses a storage battery that adsorbs carbon dioxide during charging. However, according to the study of the present inventor, the storage battery described in Non-Patent Document 1 has poor durability such as a short battery cycle life. They found that it was difficult to put it into practical use because of its poor performance.

Similar to the technology described in Non-Patent Document 1, Non-Patent Document 2 discloses a storage battery that adsorbs carbon dioxide during charging. However, primary electron acceptors of quinone compounds such as poly-1,4-anthraquinone are used to adsorb carbon dioxide, and it is known that such quinone compounds have low heat resistance. In addition, the positive electrode, which is the opposite electrode to the negative electrode in which the quinone compound is used, uses a ferrocene-type compound with iron as the central metal. compounds are used, which is economically unfavorable.

For these reasons, in order to effectively utilize carbon dioxide, there is a need to develop a secondary battery that can adsorb carbon dioxide during charging by using materials other than these materials.

As a result of various studies, the present inventor has found that the following invention achieves the above object of providing a rechargeable carbon dioxide adsorption battery while easily adsorbing carbon dioxide from a gas containing carbon dioxide. I found it.

Hereinafter, embodiments according to the present invention will be described, but the present invention is not limited thereto.

[Carbon dioxide adsorption battery]
As shown in FIGS. 1 and 2, the carbon dioxide adsorption battery 10 according to the embodiment of the present invention includes a negative electrode 11, a positive electrode 12, and a separator 16 disposed between the negative electrode 11 and the positive electrode 12. An electrolyte layer 13 is provided between the negative electrode 11 and the separator 16 and between the positive electrode 12 and the separator 16, respectively. That is, the carbon dioxide adsorption battery 10 includes a separator 16, an electrolyte layer 13 provided on both sides of the separator 16, and a negative electrode 11 and a positive electrode provided on the electrolyte layer 13 with the electrolyte layer 13 in between. 12, a pair of electrodes 11 and 12 are provided. The negative electrode 11 is an electrode that is permeable to gas. The electrolyte layer 13 includes an electrolytic solution capable of dissolving carbon dioxide and a compound having an N-oxy radical group in its molecule. Further, the separator 16 suppresses the permeation of the redox compound and allows the electrolyte to permeate. That is, the separator 16 is less permeable to the redox compound than the electrolyte. Further, the separator 16 is preferably one that allows the electrolyte to pass through but does not allow the redox compound to pass through. The carbon dioxide adsorption battery 10 may include a flow path 15 through which gas flows while contacting the negative electrode 11 . The flow path 15 is not particularly limited as long as it is a flow path through which gas can flow.

Note that FIGS. 1 and 2 are schematic cross-sectional views showing an example of the configuration of a carbon dioxide adsorption battery (the carbon dioxide adsorption battery 10) according to an embodiment of the present invention, and FIG. FIG. 2 shows the carbon dioxide adsorption battery 10 when it is being discharged.

During charging, the carbon dioxide adsorption battery 10 is arranged so that the potential of the negative electrode 11 is lower than the potential of the positive electrode 12 . A voltage is applied between the electrodes). Charging of the carbon dioxide adsorption battery 10 is not particularly limited as long as a voltage can be applied as described above. For charging the carbon dioxide adsorption battery 10 , for example , as shown in FIG . For example, charging may be performed by providing a voltage applying section 14 that applies a voltage to the battery. As shown in FIG. 2, the carbon dioxide adsorption battery 10 is discharged by providing a resistor 17 and the like between a pair of electrodes consisting of the negative electrode 11 and the positive electrode 12. Note that during charging, the negative electrode 11 serves as a cathode electrode that takes in carbon dioxide from a gas containing carbon dioxide, and during discharging, it serves as an anode electrode that releases carbon dioxide taken in during charging. Further, the positive electrode 12 becomes an anode electrode during charging , and becomes a cathode electrode during discharging.

The carbon dioxide adsorption battery 10 according to this embodiment can easily separate and adsorb carbon dioxide from a gas containing carbon dioxide. Specifically, as shown in FIG. 1, in the carbon dioxide adsorption battery 10 , the electrodes 11, When applied for 12 hours, carbon dioxide is separated from a gas containing carbon dioxide as follows. Further, the carbon dioxide adsorption battery 10 is charged by applying voltage in this manner. Therefore, in the carbon dioxide adsorption battery 10, when a gas containing carbon dioxide, such as air, is caused to flow through the flow path 15 and the carbon dioxide is brought into contact with the negative electrode 11, carbon dioxide is absorbed into the electrolyte layer 13. is adsorbed (immobilized) on the battery and simultaneously charged as a battery. Further, in the carbon dioxide adsorption battery 10, carbon dioxide is released from the electrolyte layer 13 during discharge as shown in FIG.

In the carbon dioxide adsorption battery 10, during charging, a gas having a lower carbon dioxide concentration than the gas such as air supplied from the flow path 15 is discharged, and during discharging, carbon dioxide is lowered than the gas supplied from the flow path 15. The concentrated gas is exhausted. Specifically, the gas released from the carbon dioxide adsorption battery during discharging is mainly the gas that was adsorbed by the carbon dioxide adsorption battery during charging, and therefore has a very high carbon dioxide concentration. For these reasons, the carbon dioxide adsorption battery 10 can concentrate carbon dioxide.

Therefore, the carbon dioxide adsorption battery 10 can adsorb carbon dioxide during charging and release carbon dioxide during discharge. That is, in the carbon dioxide adsorption battery 10, the affinity of carbon dioxide for the electrolyte layer 13 increases during charging, and the affinity of carbon dioxide for the electrolyte layer 13 decreases during discharge. By applying a voltage between the pair of electrodes 11 and 12, the affinity of carbon dioxide to the electrolyte layer 13 can be changed, and carbon dioxide can be adsorbed or released. . Carbon dioxide can be concentrated by this adsorption and release. Since adsorption and release of carbon dioxide is performed by applying voltage, it can be performed at room temperature, atmospheric pressure, etc.

The above mechanism of action in the carbon dioxide adsorption battery 10 is thought to be due to the following.

The negative electrode 11 can allow gas present around the negative electrode 11 to pass therethrough. When gas passes through the negative electrode 11 , the gas that has passed through the negative electrode 11 comes into contact with the electrolyte layer 13 . As a result, carbon dioxide contained in the gas existing around the negative electrode 11 is dissolved in the electrolytic solution contained in the electrolyte layer 13.

During charging, the carbon dioxide adsorption battery 10 is configured such that the negative electrode 11 is set such that the potential of the negative electrode 11 is lower than the potential of the positive electrode 12, that is, the potential of the positive electrode 12 is higher than the potential of the negative electrode 11. A voltage is applied between the pair of electrodes 11 and 12 made up of the positive electrode 12.

Since the potential of the negative electrode 11 is higher than the potential of the positive electrode 12 on the side closer to the negative electrode 11 , the redox compound contained in the electrolyte layer 13 is an N-oxy radical, as shown in the following formula (2). The group is reduced to an N-oxyanion group. Then, as shown in the following formula (3), carbon dioxide dissolved in the electrolytic solution is bonded to this N-oxyanion group, so that dissolution of carbon dioxide in the electrolytic solution is promoted. Therefore, when the carbon dioxide adsorption battery 10 is charged, carbon dioxide is taken in from the negative electrode 11 side, and carbon dioxide is adsorbed into the electrolyte layer 13.

On the other hand, since the potential of the positive electrode 12 is lower than the potential of the negative electrode 11 on the side near the positive electrode 12, the redox compound contained in the electrolyte layer 13 is -The oxy radical group is oxidized to become an N-oxycation group.

Although the separator 16 is permeable to the electrolytic solution, it suppresses permeation of the redox compound. That is, the redox compound is less likely to permeate through the separator 16 than the electrolyte. Therefore, both the redox compound whose N-oxyradical group is reduced to become an N-oxyanion group and the redox compound to which carbon dioxide is bonded are difficult to pass through the separator and migrate to the positive electrode side. Therefore, even after charging is stopped, these redox compounds are retained in the electrolyte layer 13 closer to the negative electrode 11 than the separator 16 unless discharge is performed. A redox compound whose N-oxy radical group is oxidized to become an N-oxycation group is also difficult to pass through the separator 16 and migrate to the negative electrode 11 side. Therefore, even after charging is stopped, if discharge is not performed, the redox compound having an N-oxycation group in its molecule is retained closer to the positive electrode 12 than the separator 16 of the electrolyte layer 13. For these reasons, the carbon dioxide adsorption battery 10 can maintain a charged state.

Next, when the charged carbon dioxide adsorption battery 10 is discharged, as shown in the following formula (5), the N-oxycation group changes from the N-oxycation group in the electrolyte layer 13 closer to the positive electrode 12 than the separator 16 Return to radical groups. On the side of the negative electrode 11 from the separator 16 of the electrolyte layer 13, carbon dioxide is desorbed from the redox compound as shown in the following formula (6), and N-oxyanion is formed as shown in the following formula (7). The group returns to an N-oxy radical group. Therefore, the carbon dioxide adsorption battery 10 can release carbon dioxide from the negative electrode 11 side during discharge. The gas released from the carbon dioxide adsorption battery 10 during discharging is mainly the gas that was adsorbed in the carbon dioxide adsorption battery 10 during charging, and is therefore a gas with a very high carbon dioxide concentration. From this, the carbon dioxide adsorption battery 10 can concentrate carbon dioxide.

As described above, the carbon dioxide adsorption battery 10 can adsorb carbon dioxide during charging and release carbon dioxide during discharge, and can easily adsorb carbon dioxide from a gas containing carbon dioxide while charging. It is thought that it is possible to do so. Further, it is believed that the carbon dioxide adsorption battery 10 can concentrate carbon dioxide by adsorbing and releasing carbon dioxide as described above. Furthermore, the carbon dioxide adsorption battery 10 has excellent durability because it uses a redox compound having an N-oxy radical group in its molecule, which is more durable than the quinone compound, instead of the quinone compound.

( Negative electrode )
The negative electrode 11 is not particularly limited as long as it is an electrode that can permeate gas. That is, the negative electrode 11 may be any conductive member as long as it can pass gas such as carbon dioxide and allow current to flow through the electrolyte layer 13 sandwiched between the pair of electrodes 11 and 12. Further, the negative electrode 11 is preferably a porous material that has conductivity to the extent that it does not inhibit the movement of electrons, can accumulate charges, has excellent air permeability, and has a large contact area with gas. Specifically, the negative electrode 11 includes an electrode made of a porous conductive material, and more specifically, a porous body containing carbon as a main component, a porous body consisting of carbon, and the like. Examples include porous metal layers. Examples of the porous conductive material include porous metals, porous bodies containing carbon as a main component, and porous bodies made of carbon. As the porous conductive material, these may be used alone or in combination of two or more. That is, the negative electrode 11 may be an electrode made of a single conductive material among these porous conductive materials, or an electrode made of a combination of two or more kinds of conductive materials. Good too.

Specific examples of the carbon contained in the porous body include graphite, carbon nanotubes, activated carbon such as activated carbon fibers, and carbonaceous materials such as carbon fibers. Further, the carbon is preferably graphite, carbon nanotubes, activated carbon, and carbon fiber, and from the viewpoint of corrosion resistance and specific surface area, activated carbon such as activated carbon fiber is more preferable. Further, as the carbon, various carbonaceous materials may be used alone, or two or more types may be used in combination. The porous body containing carbon is preferably a cloth-like or felt-like material made of the carbonaceous material. Therefore, specific examples of the porous electrode include a carbon sheet, carbon cloth, and carbon paper. Examples of the porous electrode include carbon-based electrodes using activated carbon or carbon fibers, and electrodes with high porosity using needle-shaped conductive materials. Further, among the above-mentioned electrodes, the electrode is preferably an electrode made of a conductive member containing at least one selected from the group consisting of graphite, carbon nanotubes, activated carbon, and carbon fibers. It is considered that such an electrode can suitably allow gas to pass through and suitably apply a voltage between the pair of electrodes 11 and 12 by the voltage applying section 14. Therefore, by using this negative electrode 11, it is possible to obtain a carbon dioxide adsorption battery that can better adsorb carbon dioxide from a gas containing carbon dioxide during charging and release carbon dioxide more suitably during discharge. It will be done.

The porous metal layer is a metal layer in which a large number of holes are formed. Further, in the porous metal layer, the pores are preferably formed over the entire metal layer in terms of excellent air permeability. In addition, as a method for obtaining the porous metal layer, a method is performed in which a metal layer in which no pores are formed (a metal layer before forming pores) is subjected to a process in which a large number of pores are formed (porous formation). method), there are no particular limitations. Examples of this method include physical methods such as cutting, polishing, and sandblasting, and chemical methods such as electrolytic etching and electroless etching using an etching solution such as an acid or a base. Moreover, as a method for making the material porous, each of the above methods may be used alone, or two or more methods may be used in combination. Further, as a method for making the material porous, a chemical method is preferable in order to make the pores (pores) to be formed more dense (to form more dense pores) from the viewpoint of increasing the surface area. Further, the material of the metal layer is not particularly limited, and examples thereof include aluminum, copper, silver, gold, iron, titanium, molybdenum, tungsten, nickel, and alloys thereof. Among these, aluminum is preferable as the material for the metal layer from the viewpoints of cost and workability. Further, the metal layer before forming the holes is preferably a so-called aluminum foil.

The BET specific surface area of the negative electrode 11 is not particularly limited, but for example, it is preferably 1 m ² /g or more, more preferably 100 m ² /g or more, and even more preferably 500 m ² /g or more. preferable. The BET specific surface area of the negative electrode 11 is preferably larger from the viewpoint of gas permeability (air permeability), but from the viewpoint of the strength of the negative electrode 11, it is preferably 3000 m ² /g or less. Therefore, the BET specific surface area of the negative electrode 11 is preferably 1 to 3000 m ² /g, more preferably 100 to 2500 m ² /g, and even more preferably 500 to 2000 m ² /g. If the BET specific surface area of the negative electrode 11 is too small, gas permeability (air permeability) tends to decrease and carbon dioxide permeation tends to be inhibited. Furthermore, if the BET specific surface area of the negative electrode 11 is too large, the strength of the electrode tends to be insufficient. For these reasons, if the BET specific surface area of the electrode 11 is within the above range, adsorption and release of carbon dioxide can be realized over a long period of time, and it can be used as a carbon dioxide battery for a long period of time. Note that the BET specific surface area is a specific surface area measured by the BET method, and can be measured by a known method. Examples of the method for measuring the BET specific surface area include a method of measuring a nitrogen adsorption isotherm and calculating from the obtained adsorption isotherm.

The negative electrode 11 may further include a current collector. That is, the negative electrode 11 may be made of the porous body, or may include the porous body and the current collector. The current collector is not particularly limited as long as it does not inhibit the permeation of the gas. As the current collector, for example, one that is made of a conductive material and has openings within a range that does not prevent gas permeation can be used. More specifically, the current collector may be made of metal such as mesh metal, punched metal, and expanded metal, or may be made by plating a woven or nonwoven fabric made of natural fibers or synthetic fibers. It may also be made conductive. Examples of metals that can be used as the current collector include stainless steel, iron, nickel, and copper.

In the negative electrode 11 including the porous body and the current collector, it is preferable that the porous body and the current collector are integrated, and the method for integrating the porous body and the current collector is not particularly limited. The integrated porous body and the current collector may be partially integrated using a method such as ultrasonic welding or plasma welding. It may also be one that ensures conductivity. Further, the integrated porous body and the current collector are made to have conductivity by interposing the porous body and the current collector with a conductive material such as a conductive adhesive. You can. The conductive material is not particularly limited, and for example, a material in which fine metal particles such as silver, gold, and nickel are dispersed, a carbon material-based conductive material, and a conductive polymer can be used.

( positive electrode )
The positive electrode 12 is not particularly limited as long as it is a conductive member that allows current to flow through the electrolyte layer 13 sandwiched between the pair of electrodes 11 and 12. It is preferable that the positive electrode 12 is, for example, an electrode provided with a gas permeation blocking portion that blocks gas permeation. Further, it is preferable that the positive electrode 12 be configured so as not to come into contact with the outside air, for example. When the positive electrode is provided with a gas permeation blocking part that blocks gas permeation, as described above, and is configured so as not to come into contact with the outside air, carbon dioxide can be easily adsorbed from a gas containing carbon dioxide. At the same time, it can be charged, and the state of charge can be maintained better. This is thought to be due to the following.

In the carbon dioxide adsorption battery 10, as described above, the separator 16 suppresses the movement of the redox compound, but the redox compound may permeate through the separator 16. For example, in the carbon dioxide adsorption battery 10, the above-described redox compound to which carbon dioxide is bound may migrate from the negative electrode 11 side to the positive electrode 12 side of the separator 16 of the electrolyte layer 13. When the redox compound to which carbon dioxide is bonded moves in this way during charging or while maintaining the charged state, the redox compound is oxidized near the positive electrode 12, and from the redox compound, Carbon dioxide is eliminated and the N-oxyanion group returns to an N-oxyradical group. At this time, when carbon dioxide is released from the positive electrode 12 side, the movement of the redox compound to which carbon dioxide is bound can be promoted. Therefore, if the positive electrode 12 is provided with a gas permeation blocking part that blocks gas permeation, and if it is configured so as not to come into contact with the outside air, such promotion of movement can be prevented, and the state of charge can be maintained. It is thought that it will be more sustainable.

In the case where the positive electrode 12 is an electrode including a gas permeation blocking part that blocks gas permeation, as shown in FIGS. Alternatively, the gas permeation shielding portion may be electrically conductive, and an electrode may be formed of the gas permeation shielding portion.

When the positive electrode 12 is an electrode including a positive electrode main body 21 and a gas permeation shielding part 22, the gas permeation shielding part 22 is provided on the opposite side of the positive electrode main body 21 from the electrolyte layer 13 side. Further, the gas permeation shielding portion 22 may be provided on the electrolyte layer 13 side of the cathode main body 21 as long as it is provided on the opposite side of the cathode main body 21 from the electrolyte layer 13 side.

The positive electrode main body 21 may be any conductive member as long as it can flow a current through the electrolyte layer 13 sandwiched between the pair of electrodes 11 and 12. Further, the positive electrode main body 21 is preferably a conductive member that has conductivity to a degree that does not inhibit the movement of electrons and can accumulate charges. Moreover, since the positive electrode main body 21 is provided with the gas permeation shielding part 22, it is preferable that gas can be permeated from the viewpoint of increasing the gas contact area. For these reasons, the positive electrode main body 21 may be the same as the conductive member exemplified as the electrode used in the negative electrode 11. Specific examples of the positive electrode body 21 include electrodes made of conductive materials such as carbon materials, metal fibers, metal foils, and conductive polymers; more specifically, carbon fibers, activated carbon, and electrodes made of graphite or the like.

The gas permeation shielding part 22 is not particularly limited as long as it can block gas permeation. Examples of the gas permeation shielding part 22 include metal foil such as aluminum foil, copper foil, and nickel foil, and plastic foil coated with conductive material paste such as conductive polymer, graphite, and silver. . Examples of the plastic foil include plastic foils containing polyethylene terephthalate (PET), polypropylene (PP), polyethylene (PE), and the like.

The electrode made of the gas permeation shielding part is an electrode configured to serve as both the positive electrode body and the gas permeation shielding part. The electrode made of the gas permeation shielding part is made of a conductive member that does not allow gases such as carbon dioxide to pass through and is capable of passing a current through the electrolyte layer 13 sandwiched between the pair of electrodes 11 and 12. Examples include electrodes.

In the case where the positive electrode 12 is configured not to come into contact with the outside air, the configuration is not particularly limited as long as the positive electrode 12 does not come into contact with the outside air. As an example of a case where the positive electrode 12 is configured so as not to come into contact with the outside air, for example, as shown in FIG. Examples include the carbon dioxide adsorption battery 20 and the like. That is, the carbon dioxide adsorption battery 20 is similar to the carbon dioxide adsorption battery 10 except that the positive electrode 12 is surrounded by the casing 25 so as not to come into contact with the outside air. In such a carbon dioxide adsorption battery 20, if the housing 25 is permeable to gas, the positive electrode 12 will not come into contact with the outside air. The casing 25 is not particularly limited as long as it does not allow gas to pass through, and may be any material that can be used as a battery casing. Note that FIG. 3 is a schematic cross-sectional view showing another example of the configuration of the carbon dioxide adsorption battery (the carbon dioxide adsorption battery 20) according to the embodiment of the present invention, and shows the carbon dioxide adsorption battery 20 during charging. .

Another example of a case where the positive electrode 12 is configured not to come into contact with the outside air is, for example, a carbon dioxide adsorption battery 30 including two negative electrodes 11 and 31 as shown in FIGS. 4 and 5. It will be done. In addition to the negative electrode 11, the carbon dioxide adsorption battery 30 further includes a negative electrode 31 different from the negative electrode 11, and also includes the electrolyte layer 13 and the separator 16 between the positive electrode 12 and the negative electrode 31. Other than this, it is the same as the carbon dioxide adsorption battery 10 described above. That is, in addition to the negative electrode 11 that constitutes the pair of electrodes 11 and 12, the carbon dioxide adsorption battery 30 further includes a negative electrode 31 that is different from this negative electrode 11, and a positive electrode 12 that constitutes the pair of electrodes 11 and 12. It is the same as the carbon dioxide adsorption battery 10 except that the electrolyte layer 13 and the separator 16 are also provided between the negative electrode 31 and the negative electrode 31 . The carbon dioxide adsorption battery 30 is the same as the carbon dioxide adsorption battery 10 except for the above. For example, the negative electrode 31 is not particularly limited as long as it is an electrode that can permeate gas. For example, Examples include the electrode used in the negative electrode 11. The carbon dioxide adsorption battery 30 having such a configuration can be configured so that the positive electrode 12 does not come into contact with the outside air. Then, as shown in FIG. 4, by applying a voltage not only between the negative electrode 11 and the positive electrode 12 but also between the positive electrode 12 and the negative electrode 31 using the voltage applying section 14, Charging can be performed not only between the negative electrode 11 and the positive electrode 12 but also between the positive electrode 12 and the negative electrode 31. Further, as shown in FIG. 5, the carbon dioxide adsorption battery 30 can also be charged between the negative electrode 11 and the positive electrode 12 and discharged between the positive electrode 12 and the negative electrode 31. Although not shown, the carbon dioxide adsorption battery 30 can also be charged between the positive electrode 12 and the negative electrode 31 and discharged between the negative electrode 11 and the positive electrode 12. 4 and 5 are schematic cross-sectional views showing another example of the configuration of the carbon dioxide adsorption battery (the carbon dioxide adsorption battery 30) according to the embodiment of the present invention. FIG. 4 shows a case where both electrodes are being charged, and FIG. 5 is a case where one electrode is being charged and the other electrode is being discharging.

As described above, the negative electrode 11 and the positive electrode 12 are electrically conductive members capable of passing a current through the electrolyte layer 13 sandwiched between the pair of electrodes 11 and 12, and the smaller the surface resistance value, the better. It is preferably, for example, 1 kΩ/sq or less, more preferably 200 Ω/sq or less. Furthermore, although it is preferable that the surface resistance value of each electrode be as small as possible, the actual limit is 1Ω/sq. Therefore, the surface resistance value of each electrode is preferably 1 Ω/sq to 1 kΩ/sq, more preferably 10 to 200 Ω/sq. With an electrode having such a surface resistance value, a current can be suitably passed through the electrolyte layer 13, and the carbon dioxide adsorption battery 10 can suitably adsorb carbon dioxide during charging, and release carbon dioxide during discharging. Carbon can be suitably released. Note that the surface resistance value of the negative electrode 31 is similar to the surface resistance values of the negative electrode 11 and the positive electrode 12.

Although the thicknesses of the negative electrode 11 and the positive electrode 12 are not particularly limited, they are preferably thick enough to suitably accumulate charge and suitably prevent electrolyte leakage. The thickness of the negative electrode 11 and the positive electrode 12 is, for example, preferably 20 μm or more and 10 mm or less, and more preferably 50 μm or more and 5 mm. If the negative electrode 11 and the positive electrode 12 are too thin, the electrodes tend to have insufficient strength or are difficult to accumulate charge. Moreover, if the negative electrode 11 and the positive electrode 12 are too thick, the carbon dioxide adsorption battery 10 tends to become too large. Furthermore, if the negative electrode 11 is too thick, gas permeability (air permeability) tends to decrease and carbon dioxide permeation tends to be inhibited. Note that the thickness of the negative electrode 31 is the same as the thickness of the negative electrode 11.

(electrolyte layer)
The electrolyte layer 13 is not particularly limited as long as it contains an electrolytic solution capable of dissolving carbon dioxide and a redox compound having an N-oxy radical group in its molecule. Further, as described above, the electrolyte layer 13 is a carbon dioxide separator that contributes to the separation of carbon dioxide by adsorbing and releasing carbon dioxide.

The thickness of the electrolyte layer 13 is not particularly limited, but is preferably, for example, 0.1 μm to 2 mm, more preferably 1 μm to 1 mm. Further, the thickness of the electrolyte layer 13 on the negative electrode 11 side and the positive electrode side are not particularly limited, but are preferably 0.1 μm to 2 mm, and more preferably 1 μm to 1 mm, respectively. preferable. If the electrolyte layer 13 is too thin, not only will the amount of carbon dioxide fixed and the amount of electricity stored decrease, but also there is a tendency for minute holes, ie, pinholes, to be formed in the electrolyte layer 13. If pinholes are formed, problems may arise, such as not being able to properly adsorb carbon dioxide or causing current to flow that does not contribute to adsorption of carbon dioxide. Furthermore, if the electrolyte layer 13 is too thick, the diffusion of carbon dioxide adsorbed in the electrolyte layer 13 within the electrolyte layer 13 becomes slow, and a discrepancy occurs between the amount of carbon dioxide fixed and the amount of electricity stored. When charging, it tends to be difficult to know whether carbon dioxide has been sufficiently adsorbed. This is thought to be due to the following. In the carbon dioxide adsorption battery 10, the contribution of the diffusion of carbon dioxide in the electrolyte layer 13 and the diffusion of the redox compound to which carbon dioxide is bound to the adsorption of carbon dioxide is greater than the contribution of the diffusion to charging. Furthermore, when the electrolyte layer 13 is thick, the influence of the diffusion becomes greater than when it is thin. For these reasons, the difference between when the electrolyte layer 13 is thick and when the electrolyte layer 13 is thin in the rate of carbon dioxide adsorption is larger than that of the electrolyte layer 13 in the rate of charge. Therefore, when the electrolyte layer 13 is thin, it is easy to understand from the amount of stored electricity that carbon dioxide has been sufficiently adsorbed, whereas when the electrolyte layer 13 is thick, as mentioned above, it is easy to understand that carbon dioxide has been sufficiently adsorbed. Since there is a discrepancy between the fixed amount and the amount of stored electricity, it is difficult to determine from the amount of stored electricity that carbon dioxide has been sufficiently adsorbed. Therefore, it is considered that the thicker the electrolyte layer 13 is, the more difficult it becomes to know that carbon dioxide has been sufficiently adsorbed during charging. Furthermore, for the same reason, if the electrolyte layer 13 is too thick, it tends to be difficult to know that carbon dioxide has been sufficiently released during discharge.

The electrolytic solution is not particularly limited as long as it can dissolve carbon dioxide, and may be an electrolytic solution containing an electrolyte and a solvent, or an electrolytic solution containing an ionic liquid. Note that an electrolytic solution that can dissolve carbon dioxide may be anything other than one in which carbon dioxide is not dissolved; in other words, an electrolytic solution that can dissolve even a small amount of carbon dioxide is sufficient, and high solubility is not required. . This is thought to be due to the following. As described above, in the carbon dioxide adsorption battery according to the present embodiment, carbon dioxide is taken into the electrolyte layer 13 on the negative electrode 11 side during charging due to the binding and desorption of carbon dioxide to the redox compound, and when discharging It is thought that adsorption and release of carbon dioxide progresses through a mechanism in which carbon dioxide is sometimes released from the electrolyte layer 13 on the negative electrode 11 side. Therefore, if even a small amount of carbon dioxide is dissolved in the electrolytic solution contained in the electrolyte layer 13, it is thought that adsorption and release of carbon dioxide will proceed.

As described above, the electrolytic solution is not particularly limited as long as it can dissolve carbon dioxide, but it is preferably nonvolatile. As described above, the electrolytic solution may be an electrolytic solution containing an electrolyte and a solvent, or an electrolytic solution containing an ionic liquid, but it must be nonvolatile and used as an electrolytic solution. Preferably one that can. Specifically, the electrolytic solution is preferably an ionic liquid.

The solvent is preferably an electrochemically stable compound with a wide potential window, and may be an aqueous solvent or an organic solvent. Examples of the solvent include water, carbonate compounds, ester compounds, ether compounds, heterocyclic compounds, nitrile compounds, and aprotic polar compounds. Examples of the carbonate compound include dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, ethylene carbonate, and propylene carbonate. Examples of the ester compound include methyl acetate, methyl propionate, and γ-butyrolactone. Examples of the ether compound include diethyl ether, 1,2-dimethoxyethane, 1,3-dioxosilane, tetrahydrofuran, and 2-methyl-tetrahydrofuran. Examples of the heterocyclic compound include 3-methyl-2-oxazodilinone and 2-methylpyrrolidone. Examples of the nitrile compound include acetonitrile, methoxyacetonitrile, propionitrile, 3-methoxypropionitrile, and valerate nitrile. Examples of the aprotic polar compound include sulfolane, dimethyl sulfoxide, and dimethylformamide. As the solvent, each of the exemplified solvents may be used alone or in combination of two or more. Among the above-mentioned solvents, examples of the solvent include carbonate compounds such as ethylene carbonate and propylene carbonate, ester compounds such as γ-butyrolactone, and complex compounds such as 3-methyl-2-oxazodilinone and 2-methylpyrrolidone. Ring compounds, nitrile compounds such as acetonitrile, methoxyacetonitrile, propionitrile, 3-methoxypropionitrile and valerate nitrile are preferred. Moreover, when using a combination of two or more types as the solvent, it is preferable to use water from the viewpoint of dissolving carbon dioxide.

The electrolyte is not particularly limited, and examples thereof include quaternary ammonium salts, inorganic salts, and hydroxides. Examples of the quaternary ammonium salts include tetramethylammonium tetrafluoroborate, tetra-n-ethylammonium tetrafluoroborate, tetra-n-propylammonium tetrafluoroborate, tetra-n-butylammonium tetrafluoroborate, and n-hexafluoroborate. Decyltrimethylammonium tetrafluoroborate, tetra-n-hexadecyl ammonium tetrafluoroborate, tetra-n-octylammonium tetrafluoroborate, tetra-n-ethylammonium perchlorate, tetra-n-butylammonium perchlorate, and tetraoctadecyl ammonium Examples include perchlorate. Examples of the inorganic salt include lithium perchlorate, sodium perchlorate, potassium perchlorate, sodium acetate, potassium acetate, sodium nitrate, and potassium nitrate. Examples of the hydroxide include sodium hydroxide and potassium hydroxide. Among the electrolytes exemplified above, examples of the electrolyte include tetramethylammonium tetrafluoroborate, tetra-n-ethylammonium tetrafluoroborate, tetra-n-propylammonium tetrafluoroborate, tetra-n-butylammonium tetrafluoroborate, and n-butylammonium tetrafluoroborate. - Hexadecyltrimethylammonium tetrafluoroborate, tetra-n-hexadecyl ammonium tetrafluoroborate, tetra-n-octylammonium tetrafluoroborate, tetra-n-ethylammonium perchlorate, tetra-n-butylammonium perchlorate, tetraoctadecyl Ammonium perchlorate, lithium perchlorate, sodium perchlorate, sodium acetate, and potassium acetate are preferred. Among these, the electrolytes include tetra-n-ethylammonium tetrafluoroborate, tetra-n-propylammonium tetrafluoroborate, tetra-n-butylammonium tetrafluoroborate, lithium perchlorate, and sodium perchlorate. Preferably, tetra-n-butylammonium tetrafluoroborate and lithium perchlorate are more preferable. Further, the electrolyte may serve as a supporting salt to stabilize carbonate ions and hydrogen carbonate ions, and may have a pH buffering ability. Specific examples of the electrolyte in this case include sodium hydrogen carbonate, sodium carbonate, acetic acid, and sodium acetate. The electrolytes listed above may be used alone or in combination of two or more.

As described above, the electrolytic solution may be an electrolytic solution containing an ionic liquid (ionic liquid). When an ionic liquid is used as the electrolytic solution, the ionic liquid can have both the functions of an electrolyte and a solvent without containing the electrolyte and the solvent as described above. Further, the electrolyte only needs to contain an ionic liquid, and may be a liquid containing an electrolyte in the ionic liquid, a liquid containing a solvent in the ionic liquid, or a liquid containing an electrolyte and the ionic liquid. It may be a liquid containing a solvent or an ionic liquid. Further, it is preferable to use an ionic liquid as the electrolyte because the ionic liquid is difficult to volatilize and has high flame retardancy.

The ionic liquid is not particularly limited as long as it is a known ionic liquid, and examples thereof include imidazolium-based ionic liquids, pyridine-based ionic liquids, alicyclic amine-based ionic liquids, and azonium amine-based ionic liquids. . Examples of the ionic liquid include 1-methyl-3-octylimidazolium tetrafluoroborate, 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium chloride, 1-butyl-3 -Methylimidazolium tetrafluoroborate, 1-decyl-3-methylimidazolium tetrafluoroborate, 1,3-dimethoxyimidazolium tetrafluoroborate, 1,3-diethoxyimidazolium tetrafluoroborate, 1-methyl-3- Octylimidazolium hexafluorophosphate, 1-ethyl-3-methylimidazolium hexafluorophosphate, 1-butyl-3-methylimidazolium hexafluorophosphate, 1-decyl-3-methylimidazolium hexafluorophosphate, 1,3- Examples include dimethoxyimidazolium hexafluorophosphate and 1,3-diethoxyimidazolium hexafluorophosphate. Among the ionic liquids exemplified above, examples of the ionic liquid include 1-methyl-3-octylimidazolium tetrafluoroborate, 1-ethyl-3-methylimidazolium tetrafluoroborate, and 1-butyl-3-methylimidazolium tetrafluoroborate. ium tetrafluoroborate, 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonylimide), 1,3-dimethoxyimidazolium tetrafluoroborate, 1-methyl-3-octylimidazolium hexafluorophosphate, and 1- Ethyl-3-methylimidazolium hexafluorophosphate is preferred. Further, as the ionic liquid, 1-methyl-3-octylimidazolium tetrafluoroborate, 1,3-dimethoxyimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonylimide), 1-Butyl-3-methylimidazolium chloride and 1-methyl-3-octylimidazolium hexafluorophosphate are more preferred, and 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonylimide), 1-butyl- More preferred are 3-methylimidazolium chloride and 1-methyl-3-octylimidazolium tetrafluoroborate.

In the electrolyte layer 13, the electrolytic solution may be gelled. Specifically, a gelling agent may be added to the electrolytic solution for gelation, or a gelling electrolyte or a polymer electrolyte may be used. Examples of the gelling agent include polymers, gelling agents using techniques such as polymer crosslinking reactions, polymerizable polyfunctional monomers, and oil gelling agents. The gelling electrolyte and the polymer electrolyte are not particularly limited as long as they can be used as a gelling electrolyte or a polymer electrolyte, such as vinylidene fluoride polymers such as polyvinylidene fluoride, polyacrylic acid, etc. Examples thereof include acrylic acid polymers such as, acrylonitrile polymers such as polyacrylonitrile, polyether polymers such as polyethylene oxide, and compounds having an amide structure in their structure.

The redox compound is not particularly limited as long as it has an N-oxy radical group in its molecule. The redox compound is preferably a redox compound that is nonvolatile and adsorbs and desorbs carbon dioxide through electrolytic reduction and electrolytic oxidation. That is, as shown in the above formula (2) and the above formula (3), the redox compound adsorbs carbon dioxide by being electrolytically reduced, and as shown in the above formula (5) and the above formula (6), , the adsorbed carbon dioxide is desorbed by electrolytic oxidation. In this redox compound, when a voltage is applied between the pair of electrodes 11 and 12 by the voltage application section 14, the N-oxy radical group is reduced to become an N-oxyanion group, and carbon dioxide is bonded to the redox compound. be done. Further, when the carbon dioxide adsorption battery 10 is discharged, carbon dioxide is desorbed and becomes an N-oxyanion group, and this N-oxyanion group is oxidized and returns to an N-oxy radical. The redox compound is thus a compound whose N-oxy radical group is changed by redox.

Specifically, the redox compound is a compound represented by the following formula (1), or a compound having a group from which one hydrogen atom has been removed from the compound represented by the following formula (1). Can be mentioned. The compound having a group from which one hydrogen atom has been removed from the compound represented by the following formula (1) may be any compound having such a group, and may be a compound bonded to another low-molecular compound. It may also be a polymer compound.

In formula (1), Z is -CR ₅ R ₆ CR ₇ R ₈ -, -CR ₉ R ₁₀ CR ₁₁ R ₁₂ CR ₁₃ R ₁₄ -, -(CR ₁₅ R ₁₆ )O-, -(CR ₁₇ R ₁₈ ) NR ₂₇ -, -(CR ₁₉ R ₂₀ )O(CR ₂₁ R ₂₂ )-, or -(CR ₂₃ R ₂₄ )NR ₂₈ (CR ₂₅ R ₂₆ )-, and R ₁ to R ₂₈ are Each independently represents a hydrogen atom or a substituent.

Preferably, at least one of R ₁ to R ₄ is a substituent, more preferably two or more are substituents, and even more preferably all four are substituents. That is, the compound represented by the formula (1) is preferably a compound in which two quaternary carbons are bonded to the N-oxy radical group. Further, the redox compound is preferably a compound in which two quaternary carbon atoms are bonded to the N-oxy radical group, or a compound having a group in which one hydrogen atom is removed from this compound. In such a compound, redox by the N-oxy radical group is likely to occur, and it is considered that the redox compound can adsorb and release carbon dioxide more favorably. Therefore, by including such a compound in the electrolyte layer, carbon dioxide can be better adsorbed from a gas containing carbon dioxide during charging, and carbon dioxide can be released better during discharging. A carbon adsorption battery is obtained.

Z in the compound represented by formula (1) is -CR ₅ R ₆ CR ₇ R ₈ -, -CR ₉ R ₁₀ CR ₁₁ R ₁₂ CR ₁₃ R ₁₄ -, -(CR ₁₉ R ₂₀ )O( CR ₂₁ R ₂₂ )- and -(CR ₂₃ R ₂₄ )NR ₂₈ (CR ₂₅ R ₂₆ )- are preferred.

Examples of the substituents in R ₁ to R ₂₈ include a hydrocarbyl group having 1 to 30 carbon atoms, a hydrocarbyloxy group having 1 to 10 carbon atoms, a hydroxy group (hydroxyl group), an optionally substituted amino group (unsubstituted or a substituted amino group), a carboxyl group, a thiol group, and an optionally substituted silyl group (unsubstituted or substituted silyl group). Furthermore, as the substituent for R ₁ to R ₂₆ , among these, a hydrocarbyl group having 1 to 30 carbon atoms, a hydroxy group, and an unsubstituted or substituted amino group are preferable. Furthermore, the substituent for R ₂₇ and R ₂₈ is preferably a hydrocarbyl group having 1 to 30 carbon atoms.

Note that "may be substituted" here refers to cases where the hydrogen atoms constituting the compound or group described immediately after are unsubstituted and cases where some or all of the hydrogen atoms are substituted with a substituent. Including both.

The hydrocarbyl group is not particularly limited, and may be linear, branched, or cyclic. Examples of the hydrocarbyl group include methyl group, ethyl group, 1-propyl group, 2-propyl group, 1-butyl group, 2-butyl group, isobutyl group, tert-butyl group, pentyl group, hexyl group, and octyl group. , decyl group, dodecyl group, 2-ethylhexyl group, 3,7-dimethyloctyl group, cyclopropyl group, cyclopentyl group, cyclohexyl group, 1-adamantyl group, 2-adamantyl group, norbornyl group, ammoniumethyl group, benzyl group, α,α-dimethylbenzyl group, 1-phenethyl group, 2-phenethyl group, vinyl group, propenyl group, butenyl group, oleyl group, eicosapentaenyl group, docosahexaenyl group, 2,2-diphenylvinyl group, 1 , 2,2-triphenylvinyl group, 2-phenyl-2-propenyl group, phenyl group, 2-tolyl group, 4-tolyl group, 4-trifluoromethylphenyl group, 4-methoxyphenyl group, 4-cyanophenyl group group, 2-biphenylyl group, 3-biphenylyl group, 4-biphenylyl group, terphenylyl group, 3,5-diphenylphenyl group, 3,4-diphenylphenyl group, pentaphenylphenyl group, 4-(2,2-diphenylphenyl group) ) Phenyl group, 4-(1,2,2-triphenylvinyl)phenyl group, fluorenyl group, 1-naphthyl group, 2-naphthyl group, 9-anthryl group, 2-anthryl group, 9-phenanthryl group, 1- Examples include pyrenyl group, chrysenyl group, naphthacenyl group, and coronyl group. Examples of the hydrocarbyl group include methyl group, ethyl group, 1-propyl group, 2-propyl group, 1-butyl group, 2-butyl group, tert-butyl group, pentyl group, hexyl group, octyl group, and decyl group. group, dodecyl group, 2-ethylhexyl group, 3,7-dimethyloctyl group, benzyl group, α,α-dimethylbenzyl group, 1-phenethyl group, 2-phenethyl group, vinyl group, propenyl group, butenyl group, oleyl group , eicosapentaenyl group, docosahexaenyl group, 2,2-diphenylvinyl group, 1,2,2-triphenylvinyl group, 2-phenyl-2-propenyl group, phenyl group, 2-tolyl group, 4- Tolyl group, 4-trifluoromethylphenyl group, 4-methoxyphenyl group, 4-cyanophenyl group, 2-biphenylyl group, 3-biphenylyl group, 4-biphenylyl group, terphenylyl group, 3,5-diphenylphenyl group, 3 , 4-diphenylphenyl group, pentaphenylphenyl group, 4-(2,2-diphenylvinyl)phenyl group, 4-(1,2,2-triphenylvinyl)phenyl group, fluorenyl group, 1-naphthyl group, 2 -naphthyl group, 9-anthryl group, 2-anthryl group, and 9-phenanthryl group are preferred. Furthermore, examples of the hydrocarbyl group include a methyl group, an ethyl group, a 1-propyl group, a 2-propyl group, a 1-butyl group, a 2-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, and a hexyl group. , octyl group, 2-ethylhexyl group, 3,7-dimethyloctyl group, benzyl group, phenyl group are more preferable, methyl group, ethyl group, 1-propyl group, 2-propyl group, 1-butyl group, More preferred are 2-butyl, isobutyl, tert-butyl, pentyl, and hexyl.

The hydrocarbyloxy group is not particularly limited, and may be linear, branched, or cyclic. Examples of the hydrocarbyloxy group include methoxy group, ethoxy group, 1-propyloxy group, 2-propyloxy group, 1-butoxy group, 2-butoxy group, isobutoxy group, tert-butoxy group, pentyloxy group, and hexyl group. Oxy group, octyloxy group, decyloxy group, dodecyloxy group, 2-ethylhexyloxy group, 3,7-dimethyloctyloxy group, cyclopropanoxy group, cyclopentyloxy group, cyclohexyloxy group, 1-adamantyloxy group, 2 -adamantyloxy group, norbornyloxy group, ammonium ethoxy group, trifluoromethoxy group, benzyloxy group, α,α-dimethylbenzyloxy group, 2-phenethyloxy group, 1-phenethyloxy group, phenoxy group, alkoxyphenoxy group, alkylphenoxy group, 1-naphthyloxy group, 2-naphthyloxy group, and pentafluorophenyloxy group. Among these, the hydrocarbyloxy group includes a methoxy group, an ethoxy group, a 1-propyloxy group, a 2-propyloxy group, a 1-butoxy group, a 2-butoxy group, a tert-butoxy group, a pentyloxy group, and a hexyloxy group. , octyloxy group, decyloxy group, dodecyloxy group, 2-ethylhexyloxy group, and 3,7-dimethyloctyloxy group are preferred. Further, as the hydrocarbyloxy group, among these, methoxy group, ethoxy group, 1-propyloxy group, 2-propyloxy group, 1-butoxy group, 2-butoxy group, isobutoxy group, tert-butoxy group, pentyloxy group, etc. and hexyloxy group are more preferred.

The amino group is not particularly limited and may be linear, branched, or cyclic. Examples of the amino group include methylamino group, ethylamino group, 1-propylamino group, 2-propylamino group, 1-butylamino group, 2-butylamino group, isobutylamino group, tert-butylamino group, Pentylamino group, hexylamino group, octylamino group, decylamino group, dodecylamino group, 2-ethylhexylamino group, 3,7-dimethyloctylamino group, cyclopropylamino group, cyclopentylamino group, cyclohexylamino group, 1-adamantyl Amino group, 2-adamantylamino group, norbornylamino group, ammonium ethylamino group, trifluoromethylamino group, benzylamino group, α,α-dimethylbenzylamino group, 2-phenethylamino group, 1-phenethylamino group , phenylamino group, alkoxyphenylamino group, alkylphenylamino group, 1-naphthylamino group, 2-naphthylamino group, and pentafluorophenylamino group. Among these, the amino group includes a methylamino group, an ethylamino group, a 1-propylamino group, a 2-propylamino group, a 1-butylamino group, a 2-butylamino group, a tert-butylamino group, and a pentylamino group. , hexylamino group, octylamino group, decylamino group, dodecylamino group, 2-ethylhexylamino group, and 3,7-dimethyloctylamino group are preferred. Further, as the amino group, among these, methylamino group, ethylamino group, 1-propylamino group, 2-propylamino group, 1-butylamino group, 2-butylamino group, isobutylamino group, tert-butyl More preferred are an amino group, a pentylamino group, and a hexylamino group.

The silyl group is not particularly limited. Examples of the silyl group include dimethylsilyl group, diethylsilyl group, diphenylsilyl group, trimethylsilyl group, triethylsilyl group, t-butyldimethylsilyl group, t-butyldiphenylsilyl group, and tristrimethylsilyl group.

As described above, the compound represented by formula (1) is preferably a compound in which two quaternary carbons are bonded to the N-oxy radical group. In this way, it is thought that by bonding a highly sterically hindered group to the site adjacent to the N-oxy radical group, the stability of the radical increases and radical coupling can be suppressed. Therefore, by including such compounds in the electrolyte layer, carbon dioxide adsorption batteries can better adsorb carbon dioxide from gases containing carbon dioxide during charging, and release carbon dioxide during discharging. is considered to be obtained.

Examples of the compound represented by the formula (1) include 1,4-di(1-oxy-2,2,6,6-tetramethyl-1-piperidin-4-yloxy)xylene, 4-acetamido- 2,2,6,6-tetramethylpiperidine 1-oxyl, N,N-di-tert-butylnitroxide radical, N,N-diphenylnitroxide radical, N,N-dinaphthylnitroxide radical, N,N-di- 2-methylphenylnitroxide radical, N,N-di-3-methylphenylnitroxide radical, N,N-di-4-methylphenylnitroxide radical, N,N-di-2-ethylphenylnitroxide radical, N,N- Di-2-propylphenyl nitroxide radical, N,N-di-2-butylphenyl nitroxide radical, N,N-di-2-pentylphenyl nitroxide radical, N,N-di-2-hexylphenyl nitroxide radical, N, N-di-2-isopropylphenyl nitroxide radical, N,N-di-2-isobutylphenyl nitroxide radical, N,N-di-2-sec-butylphenyl nitroxide radical, N,N-di-2-tert-butyl Phenyl nitroxide radical, N,N-di-4-tert-butylphenyl nitroxide radical, N,N-di-(3,5-di-tert-butyl)phenyl nitroxide radical, N,N-di-4-pyridyl nitroxide Radical, N,N-di-4-pyridazylnitroxide radical, poly(ethylene glycol)-bis-2,2,6,6-tetramethylpiperidinyloxy radical, N-phenyl-N-oxy-tert- Butylamine, N-naphthyl-N-oxy-tert-butylamine, N-tert-butyl-N-oxy-2-quinoline, 2,2,6,6-tetramethylpiperidinyloxy radical (TEMPO), 4-hydroxy -2,2,6,6-tetramethylpiperidinyloxy radical, 4-amino-2,2,6,6-tetramethylpiperidinyloxy radical, 4-carboxy-2,2,6,6-tetra Methylpiperidinyloxy radical, 4-methoxy-2,2,6,6-tetramethylpiperidinyloxy radical, 4-oxo-2,2,6,6-tetramethylpiperidinyloxy radical, 4-acetamide -2,2,6,6-tetramethylpiperidinyloxy radical, 4-octyloxy-2,2,6,6-tetramethylpiperidinyloxy radical, 2,2,5,5-tetramethylpyrrolidine- Oxy radical, 3-carbamoyl-2,2,5,5-tetramethylpyrrolidine-oxyradical, 3-carboxy-2,2,5,5-tetramethylpyrrolidine-oxyradical, 2,2,6,6-tetra Examples include methylmorpholine-N-oxy radical and 2,2,6,6-tetramethylmorpholine-piperazine-N-oxy radical.

Furthermore, as described above, the redox compound may be a polymer compound, such as a compound obtained by polymerizing the compound represented by the formula (1). Examples of the polymer compound include 4-acryloyloxy-2,2,6,6-tetramethylpiperidinyloxy radical, 4-methacryloyloxy-2,2,6,6-tetramethylpiperidinyloxy radical , 3-acryloyloxy-2,2,6,6-tetramethylpyrrolidinyloxy radical, 3-methacryloyloxy-2,2,6,6-tetramethylpyrrolidinyloxy radical, 4-vinyloyloxy-2,2 , 6,6-tetramethylpiperidylnyloxy radical, and 4-vinyloyloxy-2,2,5,5-tetramethylpyrrolidinyloxy radical, etc., as monomers. Further, the polymer compound may be a compound obtained by polymerizing the monomer alone, or a compound obtained by polymerizing a combination of two or more of the monomers. Further, the polymer compound may be a compound obtained by polymerizing the compound represented by the formula (1), or a copolymer of ethylene, propylene, butadiene, isoprene, styrene, vinyl acetate, etc. It may also be a copolymer copolymerized with a monomer. Further, these copolymer monomers may be used alone or in combination of two or more types.

Among the above-exemplified compounds, the redox compounds include 1,4-di(1-oxy-2,2,6,6-tetramethyl-1-piperidin-4-yloxy)xylene, 4-acetamido-2,2 , 6,6-tetramethylpiperidine-1-oxyl, and poly(4-methacryloyloxy-2,2,6,6-tetramethylpiperidinyloxy radical) are preferred. The redox compounds may be used alone or in combination of two or more.

The compound represented by the formula (1) may be a compound synthesized by a predetermined synthesis method, or may be a commercially available product. The synthesis method is not particularly limited as long as the compound represented by the formula (1) can be obtained, but examples thereof include a method of nitroxidation by oxidizing the amino group of a disubstituted amine compound. .

Note that non-volatile means that the substance does not evaporate or does not evaporate immediately at normal temperature and pressure. For example, as used herein, 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) is volatile rather than non-volatile. Therefore, as a guideline for non-volatility, for example, the boiling point at normal pressure is higher than 193°C, which is the boiling point of TEMPO, preferably 200°C or higher, and more preferably 220°C or higher. preferable. In addition, as a guideline for non-volatility, for example, the vapor pressure at 20°C is lower than 0.4 hPa, which is the vapor pressure (20°C) of TEMPO (that is, less than 0.4 hPa), and 0. Preferably it is less than 2 hPa (ie less than 0.2 hPa).

The electrolyte layer 13 may contain components other than the electrolytic solution and the redox compound. Examples of other components contained in the electrolyte layer 13 include polyethylene glycol, polyacrylate, polymethacrylate, and polyvinyl alcohol acetal.

The electrolyte layer 13 may include a base material. Examples of the electrolyte layer 13 include those in which the base material is impregnated with the electrolytic solution containing the redox compound. Furthermore, examples of the base material include glass fiber filter paper.

The method for manufacturing the electrolyte layer 13 is not particularly limited as long as the electrolyte layer 13 can be manufactured. When the electrolyte layer 13 includes the base material, examples include a method in which the redox compound is dispersed or dissolved in the electrolytic solution and the base material is impregnated with the electrolytic solution containing the redox compound. The impregnation is preferably performed while applying ultrasonic vibration to the electrolytic solution and the base material. By doing so, formation of minute holes, ie, pinholes, in the electrolyte layer 13 can be suppressed.

(Separator)
The separator 16 is not particularly limited as long as it is a separator that can suppress the permeation of the redox compound and allow the electrolyte to permeate. That is, the separator 16 is less permeable to the redox compound than the electrolyte. The separator 16 is preferably one that allows the electrolyte to pass through but does not allow the redox compound to pass through. The separator 16 is provided to separate the electrolyte layer 13 on the negative electrode 11 side and the electrolyte layer 13 on the positive electrode 12 side so as to allow the electrolyte to pass therethrough, but to suppress the permeation of the redox compound. It will be done. In this way, the negative electrode 11 and the positive electrode 12 are separated by the separator 16. Examples of the separator 16 include separators commonly used in lithium secondary batteries, and particularly preferred are separators that have low resistance to ion movement of the electrolyte and have excellent electrolyte moisture retention ability. . Examples of the material of the separator include glass fiber, polyester, polyethylene, polypropylene, and polytetrafluoroethylene (PTFE). The separator material may be used alone or in combination of two or more. Further, the separator is made of the same material as the separator, and may be in the form of a non-woven fabric or a woven fabric. The pore diameter of the separator is not particularly limited, and is preferably, for example, 0.01 to 10 μm. Furthermore, the thickness of the separator is not particularly limited, and is preferably, for example, 5 to 300 μm.

As described above, in the carbon dioxide adsorption battery 10, during charging, there is a gap between the pair of electrodes 11 and 12 consisting of the negative electrode 11 and the positive electrode 12 so that the potential of the negative electrode 11 is lower than the potential of the positive electrode 12. Apply voltage. For this purpose, the carbon dioxide adsorption battery 10 may be provided with the voltage application section 14. As described above, the carbon dioxide adsorption battery 10 discharges by providing a resistor 17 between the pair of electrodes 11 and 12 consisting of the negative electrode 11 and the positive electrode 12. The resistor 17 is not particularly limited as long as it can discharge the carbon dioxide adsorption battery 10.

The voltage applying section 14 is not particularly limited as long as it can apply a voltage between the pair of electrodes 11 and 12. That is, as described above, the voltage applying section 14 applies a voltage between the pair of electrodes 11 and 12 so that the potential of the negative electrode 11 is lower than the potential of the positive electrode 12. By doing so, during charging, by simply applying a voltage from the voltage applying section 14, charging can be performed while taking in carbon dioxide on the negative electrode 11 side. Further, the voltage application unit 14 may be an application unit that cannot reverse the voltage applied between the pair of electrodes 11 and 12, and includes, for example, a secondary battery, an external power source, a capacitor, etc. .

The manufacturing method of the carbon dioxide adsorption battery 10 is not particularly limited as long as it can be manufactured with the above structure. Specifically, the method for manufacturing the carbon dioxide adsorption battery 10 uses the negative electrode 11, the positive electrode 12, the electrolyte layer 13, and the separator 16, and further, if necessary, the flow path 15, Examples include a method of assembling the structure shown in FIGS. 1 and 2 using the voltage applying section 14, the resistor 17, etc. using a general assembly method.

The carbon dioxide adsorption battery 10 is charged by applying a voltage to the negative electrode 11 and the positive electrode 12. Further, during charging, the carbon dioxide adsorption battery 10 adsorbs carbon dioxide by bonding carbon dioxide to the redox compound contained in the electrolyte layer 13, as described above. The carbon dioxide adsorption battery 10 releases carbon dioxide by desorbing carbon dioxide from the redox compound contained in the electrolyte layer 13 when discharging after charging. For this reason, it is preferable that the carbon dioxide adsorption battery 10 be used so as to adsorb carbon dioxide during charging and release carbon dioxide during discharge. Further, the gas released from the carbon dioxide adsorption battery 10 during discharging is mainly the gas that was adsorbed by the carbon dioxide adsorption battery 10 during charging, and therefore has a very high carbon dioxide concentration. From this, the carbon dioxide adsorption battery 10 can concentrate carbon dioxide. That is, the carbon dioxide adsorption battery 10 can also be used as a device for concentrating carbon dioxide. Furthermore, since the carbon dioxide adsorption battery 10 adsorbs carbon dioxide from a gas containing carbon dioxide during charging and releases carbon dioxide during discharge, gas with a very high carbon dioxide concentration is released. For this reason, the carbon dioxide adsorption battery 10 can also be used as a device for separating carbon dioxide from a gas containing carbon dioxide.

[Charging/discharging device]
A charging/discharging device according to another embodiment of the present invention is a charging/discharging device including two or more of the carbon dioxide adsorption batteries. The charging/discharging device is not particularly limited as long as it includes two or more of the carbon dioxide adsorption batteries, and examples thereof include a charging/discharging device 40 as shown in FIG. 6.

The charging/discharging device 40 includes the two carbon dioxide adsorption batteries (a first carbon dioxide adsorption battery 10a and a second carbon dioxide adsorption battery 10b). The first carbon dioxide adsorption battery 10a can be charged by connecting its positive electrode side 10a2 and negative electrode side 10a1 via the voltage application section 14. That is, the charging/discharging device 40 connects the positive electrode side 10a2 of the first carbon dioxide adsorption battery 10a and the voltage application section 14 with a wiring 61, and connects the voltage application section 14 and the first carbon dioxide adsorption battery. By connecting the negative electrode side 10a1 of the battery 10a with the wiring 62, the first carbon dioxide adsorption battery 10a can be charged. After charging the first carbon dioxide adsorption battery 10a, the negative electrode side 10a1 of the first carbon dioxide adsorption battery 10a and the negative electrode side 10b1 of the second carbon dioxide adsorption battery 10b are connected with a wiring 66, and the By connecting the positive electrode side 10b2 of the second carbon dioxide adsorption battery 10b and the positive electrode side 10a2 of the first carbon dioxide adsorption battery 10a with a wiring 65, the first carbon dioxide adsorption battery 10a is discharged, The second carbon dioxide adsorption battery 10b can be charged. After charging the second carbon dioxide adsorption battery 10b (after discharging the first carbon dioxide adsorption battery 10a), the negative electrode side 10b1 of the second carbon dioxide adsorption battery 10b and the first carbon dioxide A wiring 64 connects the negative electrode side 10a1 of the adsorption battery 10a, and a wiring 63 connects the positive electrode side 10a2 of the first carbon dioxide adsorption battery 10a and the positive electrode side 10b2 of the second carbon dioxide adsorption battery 10b. Accordingly, the second carbon dioxide adsorption battery 10b can be discharged, and the first carbon dioxide adsorption battery 10a can be charged. In this way, by once charging the first carbon dioxide adsorption battery 10a, the second carbon dioxide adsorption battery 10b and the first carbon dioxide adsorption battery 10a are alternately charged and discharged. It can act as a charging/discharging device. Therefore, by including two or more of the carbon dioxide adsorption batteries, the charging/discharging device can alternately charge and discharge each of the carbon dioxide adsorption batteries. From this, this charging/discharging device becomes a charging/discharging device with high energy efficiency. Further, the charging/discharging device can separate carbon dioxide. In addition, in the first carbon dioxide adsorption battery 10a and the second carbon dioxide adsorption battery 10b, when charging, gas containing carbon dioxide (air containing nitrogen and carbon dioxide, etc.) is introduced into the flow path 15a. Nitrogen (nitrogen and unadsorbed carbon dioxide) is discharged through the flow path 15b. Further, in the first carbon dioxide adsorption battery 10a and the second carbon dioxide adsorption battery 10b, when discharging, carbon dioxide is discharged through the flow path 15c. Note that FIG. 6 is a schematic diagram showing the configuration of an example of the charging/discharging device 40 according to the embodiment of the present invention.

As described above, this specification discloses techniques in various aspects, and the main techniques are summarized below.

One aspect of the present invention is a negative electrode , a positive electrode, a separator disposed between the negative electrode and the positive electrode , and a separator disposed between the negative electrode and the separator and between the positive electrode and the separator, respectively. the negative electrode is a gas-permeable electrode, and the electrolyte layer includes an electrolytic solution capable of dissolving carbon dioxide and a redox compound having an N-oxy radical group in the molecule. , the separator is a carbon dioxide adsorption battery in which the separator suppresses permeation of the redox compound and allows the electrolyte to permeate.

According to such a configuration, it is possible to provide a rechargeable carbon dioxide adsorption battery while easily adsorbing carbon dioxide from a gas containing carbon dioxide.

This is thought to be due to the following.

The negative electrode may allow gas present around the negative electrode to pass therethrough. When gas passes through the negative electrode , the gas that has passed through the negative electrode comes into contact with the electrolyte layer. As a result, carbon dioxide contained in the gas existing around the negative electrode is dissolved in the electrolytic solution contained in the electrolyte layer.

During charging, the carbon dioxide adsorption battery is configured such that a voltage between the negative electrode and the positive electrode is set such that the potential of the negative electrode is lower than the potential of the positive electrode, that is, the potential of the positive electrode is higher than the potential of the negative electrode. Apply voltage to.

In the redox compound contained in the electrolyte layer, since the potential of the negative electrode is higher than the potential of the positive electrode on the side closer to the negative electrode, the N-oxy radical group is reduced to become an N-oxyanion group. Since the carbon dioxide dissolved in the electrolyte is bonded to this N-oxyanion group, dissolution of carbon dioxide in the electrolyte is promoted. Therefore, when the carbon dioxide adsorption battery is charged, carbon dioxide is taken in from the negative electrode side, and carbon dioxide is adsorbed in the electrolyte layer.

On the other hand, in the redox compound contained in the electrolyte layer, on the side closer to the positive electrode , since the potential of the positive electrode is lower than the potential of the negative electrode, N-oxy radical groups are oxidized and converted to N-oxycation groups. Become.

Although the separator is permeable to the electrolyte, it suppresses permeation of the redox compound. That is, the redox compound is less likely to permeate through the separator than the electrolyte. Therefore, both the redox compound whose N-oxyradical group is reduced to become an N-oxyanion group and the redox compound to which carbon dioxide is bonded are difficult to pass through the separator and migrate to the positive electrode side. Therefore, even after charging is stopped, these redox compounds are retained in the electrolyte layer closer to the negative electrode than the separator unless discharged. A redox compound whose N-oxyradical group is oxidized to become an N-oxycation group is also difficult to pass through the separator and migrate to the negative electrode side. Therefore, even after charging is stopped, if discharge is not performed, the redox compound having an N-oxycation group in its molecule is retained closer to the positive electrode than the separator of the electrolyte layer. For these reasons, the carbon dioxide adsorption battery can maintain a charged state.

As described above, it is thought that the carbon dioxide adsorption battery can be charged while easily adsorbing carbon dioxide from a gas containing carbon dioxide. Furthermore, the carbon dioxide adsorption battery has excellent durability because it uses a redox compound having an N-oxy radical group in its molecule, which is more durable than the quinone compound, instead of the quinone compound.

As described above, when the charged carbon dioxide adsorption battery is discharged, the N-oxycation groups return to N-oxyradical groups on the positive electrode side of the electrolyte layer from the separator. On the negative electrode side of the electrolyte layer from the separator, carbon dioxide is desorbed from the redox compound, and the N-oxyanion group returns to an N-oxyradical group. Therefore, the carbon dioxide adsorption battery can release carbon dioxide from the negative electrode side during discharge. The gas released from the carbon dioxide adsorption battery during discharging is mainly the gas that was adsorbed by the carbon dioxide adsorption battery during charging, and therefore has a very high carbon dioxide concentration. This means that the carbon dioxide adsorption battery can concentrate carbon dioxide.

Therefore, the carbon dioxide adsorption battery can adsorb carbon dioxide during charging and release carbon dioxide during discharge, and carbon dioxide can be concentrated by this adsorption and release. Further, since this adsorption and release is performed by applying a voltage between the negative electrode and the positive electrode , there is no need to raise the temperature or pressure, and the adsorption and release can be performed at room temperature and atmospheric pressure.

Further, in the carbon dioxide adsorption battery, it is preferable that the positive electrode includes a gas permeation blocking portion that blocks gas permeation.

According to such a configuration, it is possible to charge the battery while easily adsorbing carbon dioxide from a gas containing carbon dioxide, and it is possible to better maintain the charged state.

Further, in the carbon dioxide adsorption battery, it is preferable that the positive electrode is configured so as not to come into contact with outside air.

According to such a configuration, it is possible to charge the battery while easily adsorbing carbon dioxide from a gas containing carbon dioxide, and it is possible to better maintain the charged state.

In the case where the positive electrode includes a gas permeation blocking part that blocks gas permeation, and in the case where it is configured so as not to come into contact with the outside air, carbon dioxide can be easily adsorbed from a gas containing carbon dioxide as described above. However, the fact that the battery can be charged and the state of charge can be better maintained is considered to be due to the following.

In the carbon dioxide adsorption battery, as described above, the separator suppresses the movement of the redox compound, but the redox compound may permeate through the separator. For example, in the carbon dioxide adsorption battery, the above-described redox compound to which carbon dioxide is bound may migrate from the negative electrode side to the positive electrode side of the separator of the electrolyte layer. When the redox compound to which carbon dioxide is bound moves in this way during charging or while maintaining the charged state, the redox compound is oxidized near the positive electrode , and the redox compound is converted into carbon dioxide. Carbon is eliminated and the N-oxyanion group returns to an N-oxyradical group. At this time, when carbon dioxide is released from the positive electrode side, movement of the redox compound to which carbon dioxide is bound can be promoted. Therefore, if the positive electrode is provided with a gas permeation blocking part that blocks gas permeation, and if it is configured so as not to come into contact with the outside air, it is possible to prevent such acceleration of movement from occurring, and the state of charge can be further improved. It is thought that it can be maintained.

Furthermore, as described above, the carbon dioxide adsorption battery adsorbs carbon dioxide during charging and releases carbon dioxide during discharge. For this reason, it is preferable that the carbon dioxide adsorption battery be used so as to adsorb carbon dioxide during charging and release carbon dioxide during discharging.

Further, in the carbon dioxide adsorption battery, the redox compound is preferably a compound in which two quaternary carbons are bonded to the N-oxy radical group.

According to such a configuration, more carbon dioxide can be adsorbed from the gas containing carbon dioxide, and the state of charge can be better maintained. This is considered to be due to the fact that carbon dioxide can be bonded to and desorbed from the redox compound more appropriately.

Further, in the carbon dioxide adsorption battery, the redox compound has a compound represented by the following formula (1) or a group from which one hydrogen atom has been removed from the compound represented by the following formula (1). Preferably, it is a compound.

In formula (1), Z is -CR ₅ R ₆ CR ₇ R ₈ -, -CR ₉ R ₁₀ CR ₁₁ R ₁₂ CR ₁₃ R ₁₄ -, -(CR ₁₅ R ₁₆ )O-, -(CR ₁₇ R ₁₈ ) NR ₂₇ -, -(CR ₁₉ R ₂₀ )O(CR ₂₁ R ₂₂ )-, or -(CR ₂₃ R ₂₄ )NR ₂₈ (CR ₂₅ R ₂₆ )-, and R ₁ to R ₂₈ are Each independently represents a hydrogen atom or a substituent.

According to such a configuration, more carbon dioxide can be adsorbed from the gas containing carbon dioxide, and the state of charge can be better maintained. This is considered to be due to the fact that carbon dioxide can be bonded to and desorbed from the redox compound more appropriately.

Further, in the carbon dioxide adsorption battery, it is preferable that the negative electrode is made of a conductive material containing at least one member selected from the group consisting of graphite, carbon nanotubes, activated carbon, and carbon fibers.

According to such a configuration, more carbon dioxide can be adsorbed from the gas containing carbon dioxide, and the state of charge can be better maintained. This is thought to be due to the fact that carbon dioxide can more appropriately permeate through the negative electrode , and that a voltage can be more appropriately applied between the negative electrode and the positive electrode during charging.

Another aspect of the present invention is a charging/discharging device including two or more of the carbon dioxide adsorption batteries.

According to such a configuration, as described above, a charging/discharging device including the carbon dioxide adsorption battery can be provided. Furthermore, by including two or more of the carbon dioxide adsorption batteries, the charging/discharging device can alternately charge and discharge each of the carbon dioxide adsorption batteries. Specifically, first, one of the carbon dioxide adsorption batteries (first battery) is charged. Thereafter, the other carbon dioxide adsorption battery (second battery) connected to the first battery can be charged by discharging the first battery. Thereafter, by discharging the second battery, the first battery can be charged. In this manner, by once charging the first battery, it is possible to cause the second battery and the first battery to act as a charging/discharging device that can alternately repeat charging and discharging. From this, this charging/discharging device becomes a charging/discharging device with high energy efficiency. Further, the charging/discharging device can separate carbon dioxide.

According to the present invention, it is possible to provide a carbon dioxide adsorption battery that can be charged while easily adsorbing carbon dioxide from a gas containing carbon dioxide. Further, according to the present invention, a charging/discharging device including the carbon dioxide adsorption battery can be provided.

EXAMPLES The present invention will be specifically described below with reference to Examples, but the present invention is not limited thereto.

[Example 1]
<Preparation of carbon dioxide adsorption battery>
A carbon dioxide adsorption battery having the structure shown in FIGS. 1 and 2 was manufactured using the following procedure.

(electrolyte layer)
6.5 g of Poly (vinylidenefluoride-co-hexafluoropropylene) (manufactured by Sigma-Aldrich) was added to 100.0 g of dimethylformamide (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), and dissolved by stirring at 80° C. for 3 hours. . Next, the redox compound 4-methacryloyloxy-2,2,6,6-tetramethylpiperidinyloxy radical (manufactured by Tokyo Chemical Industry Co., Ltd.) was added to the obtained solution as a monomer, and a conventional method was added. 24.0 g of a compound [poly(4-methacryloyloxy-2,2,6,6-tetramethylpiperidinyloxy radical)] (nonvolatile) obtained by polymerization by anionic polymerization method was added, and Stir for hours to dissolve. Next, an ionic liquid [1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide (non-volatile) (emimFSI manufactured by Sigma-Aldrich), which is an electrolytic solution capable of dissolving carbon dioxide, is added to the obtained solution. ]12.9g was added, heated to 40°C, and stirred and mixed for 3 hours. Using the liquid thus obtained, a liquid film with a thickness of 500 μm was formed on a glass plate using an applicator, and the film was dried under reduced pressure at 60° C. for 8 hours. The dried film obtained by the drying process was peeled off from the glass plate. By doing so, a dry film with a thickness of 100 μm was obtained. The obtained dried membrane was cut into a size of 20 mm in length x 24 mm in width and used as an electrolyte layer. When the obtained electrolyte layer was visually inspected, no minute holes (pinholes) were observed.

(Electrode: negative electrode and positive electrode )
A plurality of sheets of carbon paper (GDL35BC manufactured by SGL Carbon Japan Co., Ltd.) were cut into a size of 30 mm long x 30 mm wide x 1 mm thick.

As the negative electrode , a conductive copper foil tape (used as a tab) was attached to one side of the cut out carbon paper.

As a positive electrode , a copper foil ( gas permeation shielding part) measuring 30 mm long x 30 mm wide x 8 mm thick was attached to one side of the cut carbon paper (positive electrode body) using a conductive adhesive (Dotite D manufactured by Fujikura Kasei Co., Ltd.). -550) (a positive electrode comprising a positive electrode body and a gas permeation shielding part) was used.

(Separator)
As the separator, a polypropylene separator (Celguard #2400 manufactured by Polypore Co., Ltd.) cut into a size of 30 mm in length x 30 mm in width was used.

(flow path)
A resin plate made of polytetrafluoroethylene was cut into a size of 50 mm long x 50 mm wide x 5 mm thick, and two holes were punched at appropriate locations. A groove with a depth of 1 mm, a length of 20 mm, and a width of 20 mm was dug in the cut resin plate to connect with the hole. This was used as a flow path.

(carbon dioxide adsorption battery)
The electrolyte layer is laminated on both sides of the separator, and the negative electrode is laminated on one side of the separator, and the positive electrode is laminated on the other side of the separator. A carbon dioxide adsorption battery was manufactured to have a structure as shown in FIGS. 1 and 2, except that a channel was also formed on the positive electrode side by assembling the channel. In the carbon dioxide adsorption battery manufactured here, a flow path was also formed on the positive electrode side in order to confirm that there was no gas leakage from the positive electrode side. When charging the carbon dioxide adsorption battery, as shown in FIG. 1, a power source serving as a voltage application section was connected to the conductive copper foil tape of the negative electrode and the copper foil of the positive electrode. Furthermore, during discharge, in the carbon dioxide adsorption battery, a resistor was connected to the conductive copper foil tape of the negative electrode and the copper foil of the positive electrode, as shown in FIG.

[evaluation]
The carbon dioxide adsorption battery was evaluated using the following evaluation method.

First, the carbon dioxide adsorption battery was placed in an environment at room temperature (28° C.), and a gas bag filled with carbon dioxide was attached to the hole in the channel on the negative electrode ( anode side electrode during discharge ) side. A gas bag filled with nitrogen was attached to the hole in the channel on the positive electrode ( cathode side electrode during discharge ) side. A portable carbon dioxide gas concentration meter (CGP manufactured by DKK Toa Co. , Ltd. -31) was installed. The dioxide concentration measured during this installation was 0.4% (4000 ppm). Then, by adjusting the power supply, the voltage between the electrodes (between the negative electrode and the positive electrode) is charged to 4V with a constant current of 0.25 mA, and then the voltage is discharged to 3V. The discharge characteristics of the carbon dioxide adsorption battery were measured. Specifically, the discharge characteristics of the carbon dioxide adsorption battery were measured (discharge rate characteristics evaluation) as follows.

Discharge rate characteristic evaluation Using a charge/discharge test device (TOSCAT manufactured by Toyo System Co., Ltd.), the carbon dioxide adsorption battery was charged at a constant current of 2.5 mA until the voltage reached 4 V, and then Constant voltage charging was performed at 4V until the voltage reached 0.25mA. Thereafter, constant current discharge was performed at a discharge current of 1 C (2.5 mA), and the discharge capacity (mAh/g) at that time was measured. Note that the discharge capacity was determined as the capacity per weight of the radical material in order to facilitate comparison of the efficiency of the radical material.

When measuring this discharge rate characteristic evaluation, after the completion of the charging, a portable carbon dioxide gas concentration meter (CGP-31 manufactured by DKK Toa Co., Ltd.) was attached to the hole in the flow path on the side of the negative electrode ( anode side electrode during discharging ). The residual carbon dioxide concentration (CO ₂ concentration after charging) was measured. Further, after the discharge, the carbon dioxide concentration (CO ₂ concentration after discharge) was measured with a portable carbon dioxide gas concentration meter attached to the hole in the channel on the side of the negative electrode ( anode side electrode during discharge ). In addition, it was confirmed that no gas leaked from the flow path formed on the positive electrode side.

These results are shown in Table 1.

[Example 2]
As an electrolyte (ionic liquid) that can dissolve carbon dioxide, 1-butyl-3-methylimidazolium is used instead of poly(4-methacryloyloxy-2,2,6,6-tetramethylpiperidinyloxy radical). A carbon dioxide adsorption battery was produced in the same manner as in Example 1 except that 42.9 g of bis(trifluoromethylsulfonylimide) was used. Then, the same evaluation as in Example 1 was performed using the obtained carbon dioxide adsorption battery. In addition, it was confirmed that no gas leaked from the flow path formed on the positive electrode side.

These results are shown in Table 1.

[Example 3]
As the positive electrode , the same electrode as the negative electrode (a conductive copper foil tape (used as a tab) was pasted on one side of the cut out carbon paper) was used instead of a positive electrode comprising a positive electrode body and a gas permeation shielding part. A carbon dioxide adsorption battery was manufactured in the same manner as in Example 1, except that the positive electrode was not equipped with a gas permeation shielding part. Then, the same evaluation as in Example 1 was performed using the obtained carbon dioxide adsorption battery. In addition, it was confirmed that no gas leaked from the flow path formed on the positive electrode side.

These results are shown in Table 1.

[Example 4]
The same procedure as in Example 1 was carried out, except that the following negative electrode was used instead of a conductive copper foil tape (used as a tab) attached to one side of the cut out carbon paper as the negative electrode. , manufactured a carbon dioxide adsorption battery. Then, the same evaluation as in Example 1 was performed using the obtained carbon dioxide adsorption battery. In addition, it was confirmed that no gas leaked from the flow path formed on the positive electrode side.

These results are shown in Table 1.

Activated carbon (YP-50 manufactured by Kuraray Co., Ltd.), styrene-butadiene rubber (SBR) (TRD2001 manufactured by JSR Corporation), carboxymethyl cellulose (CMC) (Celogen BSH manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), and carbon Black (Super-P manufactured by TIMCAL Graphite & Carbon) was mixed with water so that activated carbon: SBR: CMC: carbon black = 90:3:2:5 (mass ratio) to obtain a slurry. Instead of carbon paper, a stainless steel mesh (stainless steel mesh manufactured by Kurubaa Co., Ltd., stainless steel 304, mesh number 635) was used, and the obtained slurry was coated on this stainless steel mesh with a bar coater. After the process, it was dried in a glass tube oven at 150° C. for 7 hours under reduced pressure to obtain an activated carbon-coated electrode (activated carbon portion thickness: 150 μm). This electrode was used as a negative electrode .

[Comparative example 1]
Obtained by polymerizing the redox compound 4-methacryloyloxy-2,2,6,6-tetramethylpiperidinyloxy radical (manufactured by Tokyo Chemical Industry Co., Ltd.) by a conventional anionic polymerization method as a monomer. 28.4 g of the compound [poly(4-methacryloyloxy-2,2,6,6-tetramethylpiperidinyloxy radical)] (nonvolatile) was dissolved in 30.0 g of toluene. The solution thus obtained was dropped onto the entire surface of a glass fiber filter paper (GC50 manufactured by ADVANTEC). Thereafter, the glass fiber filter paper onto which the solution had been dropped was dried under a nitrogen atmosphere. By doing so, toluene was removed and a solid electrolyte layer was obtained. A device was manufactured in the same manner as in Example 1 except that this solid electrolyte layer was used. Then, using the obtained device, the same evaluation as in Example 1 was performed. In addition, it was confirmed that no gas leaked from the flow path formed on the positive electrode side. Furthermore, since this device does not adsorb carbon dioxide or store electricity, it is simply referred to as a device.

These results are shown in Table 1.

[Comparative example 2]
A carbon dioxide adsorption battery was manufactured in the same manner as in Example 1, except that no redox compound was added. Then, the same evaluation as in Example 1 was performed using the obtained carbon dioxide adsorption battery. In addition, it was confirmed that no gas leaked from the flow path formed on the positive electrode side. Furthermore, since this device does not adsorb carbon dioxide or store electricity, it is simply referred to as a device.

These results are shown in Table 1.

In Table 1, "-" in the discharge capacity column indicates that electricity could not be stored (charged state could not be maintained).

[Comparative example 3]
As the positive electrode , the same electrode as the negative electrode (a conductive copper foil tape (used as a tab) was pasted on one side of the cut out carbon paper) was used instead of a positive electrode comprising a positive electrode body and a gas permeation shielding part. A device was manufactured in the same manner as in Example 1, except that a separator was used and no separator was provided. Note that this device is called a carbon dioxide separator because it neither adsorbs carbon dioxide nor stores electricity.

First, the carbon dioxide separator is installed in an environment at room temperature (28°C), and a gas bag filled with carbon dioxide is inserted into the hole in the flow path on the anode side electrode during discharge. A gas pack filled with nitrogen was attached to the hole in the road. Subsequently, the portable carbon dioxide concentration meter was attached to each of the holes in the flow path on the anode side electrode side during discharge and the holes in the flow path on the cathode side electrode side during discharge . The dioxide concentration measured during this installation was 0.4% (4000 ppm). Then, by adjusting the power source, a constant current of 0.25 mA was applied between the electrodes until the voltage reached 4V.

In the carbon dioxide separator, by applying a voltage, the carbon dioxide concentration measured by the anode-side carbon dioxide concentration meter during discharge decreases, and the carbon dioxide concentration measured by the cathode-side carbon dioxide concentration meter during discharge increases. I started. Thereafter, after applying voltage for 2 hours, the voltage application was stopped and the current was stopped, and the voltage between the two electrodes immediately decreased, confirming that the device was not charged. Further, the carbon dioxide concentration measured by the anode-side carbon dioxide gas concentration meter during discharge was 270 ppm, and the carbon dioxide concentration measured by the cathode-side carbon dioxide gas concentration meter during discharge was 3520 ppm. In this device, by applying a voltage, carbon dioxide can be permeated from the cathode side during charging to the anode side during charging , but charging was not possible.

As can be seen from Table 1, in the battery comprising the negative electrode , the positive electrode, the separator, and the electrolyte layer, the electrolyte layer contains an electrolytic solution capable of dissolving carbon dioxide and an N-oxy radical group in the molecule. The carbon dioxide adsorption batteries (Examples 1 to 4) containing the redox compound were chargeable. Furthermore, in the carbon dioxide adsorption batteries according to Examples 1 to 4, it was confirmed that carbon dioxide was adsorbed because the carbon dioxide concentration on the negative electrode side decreased during charging. Further, in the carbon dioxide adsorption batteries according to Examples 1 to 4, when the carbon dioxide adsorption batteries are charged and then discharged, the carbon dioxide concentration on the negative electrode side almost returns to the concentration before charging, so that the adsorbed carbon dioxide is not released. It could be confirmed.

On the other hand, when a solid electrolyte layer made of a redox compound that does not contain an electrolyte that can dissolve carbon dioxide and has an N-oxy radical group in its molecule (Comparative Example 1), charging was not possible. , it was not possible to store electricity. Furthermore, in the device according to Comparative Example 1, even when a voltage was applied between the electrodes to charge the device, the carbon dioxide concentration on the negative electrode side did not decrease, and it was confirmed that carbon dioxide was not adsorbed. In addition, when an electrolyte layer containing an electrolytic solution capable of dissolving carbon dioxide but not containing a redox compound having an N-oxy radical group in the molecule (Comparative Example 2) is used, the device according to Comparative Example 1 is the same. , could not be charged or stored power. Further, in the device according to Comparative Example 2, even when a voltage was applied between the electrodes to charge the device, the carbon dioxide concentration on the negative electrode side did not decrease, and it was confirmed that carbon dioxide was not adsorbed. The reason these devices could not be charged and carbon dioxide was not adsorbed even when a voltage was applied between the electrodes to charge them is that even if a voltage was applied between the electrodes to charge them, the redox compound did not absorb carbon dioxide. This is thought to be due to the inability of carbon dioxide to bind.

Furthermore, in the case where the separator was not provided (Comparative Example 3), charging was not possible and electricity could not be stored. In the device according to Comparative Example 3, when a voltage was applied between the electrodes to charge the device, the carbon dioxide concentration on the negative electrode side decreased, and it was confirmed that carbon dioxide was adsorbed. This is thought to be due to carbon dioxide being bonded to the redox compound. On the other hand, while a voltage is applied between the electrodes for charging, the carbon dioxide concentration on the anode side increases during charging , and this confirms that carbon dioxide is being released from the electrodes. Ta. This is thought to be because the redox compound to which carbon dioxide is bonded reaches the anode side electrode during charging due to the absence of a separator, and carbon dioxide is desorbed from the redox compound there. From this, it is considered that the device according to Comparative Example 3 cannot be charged and cannot store electricity.

This application is based on Japanese Patent Application No. 2021-034204 filed on March 4, 2021, and the contents thereof are included in the present application.

In order to express the present invention, the present invention has been appropriately and fully described through the embodiments above, but it is understood that those skilled in the art can easily modify and/or improve the above-described embodiments. should be recognized as such. Therefore, unless the modification or improvement made by a person skilled in the art does not depart from the scope of the claims stated in the claims, such modifications or improvements do not fall outside the scope of the claims. It is interpreted as encompassing.

According to the present invention, a carbon dioxide adsorption battery that can be charged while easily adsorbing carbon dioxide from a gas containing carbon dioxide is provided. Further, according to the present invention, a charging/discharging device including the carbon dioxide adsorption battery is provided.

Claims (8)

a negative electrode ;
a positive electrode ;
a separator disposed between the negative electrode and the positive electrode ;
an electrolyte layer disposed between the negative electrode and the separator and between the positive electrode and the separator,
the negative electrode is an electrode that is permeable to gas;
The electrolyte layer includes an electrolytic solution capable of dissolving carbon dioxide and a redox compound having an N-oxy radical group in the molecule,
A carbon dioxide adsorption battery, wherein the separator suppresses permeation of the redox compound and allows permeation of the electrolyte. The carbon dioxide adsorption battery according to claim 1, wherein the positive electrode includes a gas permeation blocking portion that blocks gas permeation. The carbon dioxide adsorption battery according to claim 1, wherein the positive electrode is configured not to come into contact with outside air. The carbon dioxide adsorption battery according to any one of claims 1 to 3, which adsorbs carbon dioxide during charging and releases carbon dioxide during discharge. The carbon dioxide adsorption battery according to any one of claims 1 to 4, wherein the redox compound is a compound in which two quaternary carbon atoms are bonded to the N-oxy radical group. The redox compound is a compound represented by the following formula (1) or a compound having a group from which one hydrogen atom has been removed from the compound represented by the following formula (1). The carbon dioxide adsorption battery according to any one of the items.

[In formula (1), Z is -CR ₅ R ₆ CR ₇ R ₈ -, -CR ₉ R ₁₀ CR ₁₁ R ₁₂ CR ₁₃ R ₁₄ -, -(CR ₁₅ R ₁₆ )O-, -(CR ₁₇ R ₁₈ )NR ₂₇ -, -(CR ₁₉ R ₂₀ )O(CR ₂₁ R ₂₂ )-, or -(CR ₂₃ R ₂₄ )NR ₂₈ (CR ₂₅ R ₂₆ )-, and R ₁ to R ₂₈ are , each independently represents a hydrogen atom or a substituent. ] The carbon dioxide adsorption battery according to any one of claims 1 to 6, wherein the negative electrode is made of a conductive material containing at least one member selected from the group consisting of graphite, carbon nanotubes, activated carbon, and carbon fibers. A charging/discharging device comprising two or more carbon dioxide adsorption batteries according to any one of claims 1 to 7.